Genotypes for linkage and association were carried out in support of investigators in the current SCOR. A total of 41 separate marker systems from 21 genes were run. In all, 6,647 genotypes were obtained for this study. As new samples were arriving at the Core throughout the course of the grant, not all of the samples have been typed for all marker systems, however, an effort was made to complete typing on the new samples for key marker systems that yielded promising results in the original analysis. The Molecular Genetics core currently is completing the genotyping on the last group of a total of 214 sibling pair samples and for association studies and an additional 120 singleton samples for a total of 434 DNA samples. Linkage markers close to candidate genes as well as single nucleotide polymorphism (SNPs) within the candidate genes were run. Linkage markers were carried out using a radioactive/acrylamide detection system. SNPs were detected with either mass spectrometry, the allelic discrimination system of the Perkin-Elmer ABI Prism 7700, or restriction enzyme digestion followed by resolution on agarose gels.